The broadcaster said advertising revenue will be down by 10 per cent in April., according to early indications.
It comes as ITV revealed that advertising revenue was down 1.5 per cent last year, beating its own predictions of a 2 per cent fall.
Chief executive Carolyn McCall said: "Thanks to the hard work of our teams across the business, our full year results have come in ahead of expectations helped by revenue growth in the second half of the year in ITV Studios, advertising and online.
"We are making good progress in each area of our strategy and our investments in data, technology, online and in streaming will enable ITV to be a sustainable, diversified and structurally-sound digital media and entertainment business."
ITV said the outlook for 2020 is on track to deliver the firm'smedium term targets.
"We have started the year well with very strong online viewing up 89 per cent driven particularly by The Masked Singer and Love Island," said Ms McCall.
"We have a strong schedule coming up with the return of Saturday Night Takeaway, new entertainment show The Epic Gameshow, dramas including the second series of The Bay, and Quiz, and the European Football Championships."